shell script timing various commands

The time taken to execute a particular command (e.g. ls -ltr) can be saved to a file.
This can be useful when your shell script takes a lot of time and you want to profile the time taken by various commands.

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#!/bin/bash

"Time taken by ls" 2>> time.txt
{ time {
ls -ltr
} } 2>> time.txt

"Time taken by cat" 2>> time.txt
{ time {
cat test.sh;
} } 2>> time.txt

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